Water cooled stoker



Aug- 25, 1942- J. s. BENNETT WATER COOLED STOKER Filed Nov. 1, 1938 s Sheets-Sheet 1 M. m 8 W #3 Z w l A T ii. x

Aug. 25, 1942. J s BENNETT 2,294,269

' WATER COOLED STOKER Filed Nov. 1, 1938 3 Sheets-Sheet 2 Aug 25, 1942. J. 5. BENNETT WATER COOLED STOKER Filed Nov. 1, 1938 3 Sheets-Sheet 5 Patented Aug. 25, 1942 WATER COOLED ST'OKER Joseph S. Bennett, Merion, Pa., assignor to American Engineering Company, Philadelphia, Pa., a corporation of Pennsylvania.

Application November 1, 1938, Serial No. 238,154

13 Claims.

This invention relates to stoker furnaces, and more particularly to stoker furnaces of the fluid cooled type.

One object of the present invention is to provide a generally improved and simplified stoker furnace which employs fluid conducting tubes for cooling th grates and chilling any molten slag in the vicinity thereof.

A more specific object is to provide in a stoker furnace of the stated character tuyeres composed of members welded to the tubes provided over the tuyere chambers, the said tuyres being so constructed and arranged that the heat absorbed thereby is rapidly conducted to the fluid circulating in said tubes, whereby said tuyeres remain relatively cool under operating conditions.

Other and further objects will become apparent as the description of the invention progresses.

Of the drawings:

Fig. 1 is a longitudinal sectional view taken through one of the retorts of an underfeed stoker, showing the fluid cooled tuyeres associated therewith.

Fig. 2 is a sectional view taken substantially along line 22 of Fig. 1 showing the structure and arrangement of a tuyere assembly.

Fig. 3 is a fragmentary plan view of the stoker shown in Fig. 1, with parts removed to show the supporting means for the tubes disposed above the tuyere chambers.

Fig. 4 is a sectional View taken transversely of one of the tuyere chambers of a stoker furnace, showing a modified type of tuyere construction.

Fig. 5 is a similar view showing a further modifled type of tuyere construction.

Fig. 6 is a View similar to Figs. 4 and 5, showing a still further modified type of tuyre construction.

Fig. '7 is a side elevational view of the construction shown in Fig. 6 with parts removed to disclose more fully the construction of the tuyres.

Fig. 8 is a plan view of the constructions shown in Figs. 6 and 7, and

Fig. 9 is a sectional view taken transversely. of one of the tuyre chambers of the stoker furnace showing a further modification of the present invention.

Referring to the drawings, the numeral l desnates e r y a i ned grate toke o th underfeed type consisting of alternately disposed retorts 2 and tuyere rows 3. The side walls of the retorts comprise spaced side plates 4 and 5 supported at the upper and lower ends thereof by any suitable supporting structures 6 and 1 v respectively. The bottom of each retort com prises a series of alternately disposed pushers. 8 and dead plates 9. Fuel is supplied to the stoker from hoppers 10 disposed exteriorly of the front wall ll of the furnace. The fuel gravitating in said hoppers enters cylinders I2 from which it is fed to the stoker by means of rams I3. Rams I3 are reciprocated by any suitable power mechanism [4 through a link and lever mechanism 15. The pushers 8 are also reciprocated by the power mechanism l3 through any suitable link and lever mechanism indicated generally at. [6.

The tuyere chambers I! disposed between adjacent retorts are defined at the sides, thereof by. the retort side plates 4 and 5, as-shown more particularly in Fig. 2. Mounted at the upper end of side plates 4 and 5. are series of sectional tuyre supports, l8 and I9. Each tuyre support [.8 and I9 has provided at the lower end thereof an inwardly extending flange 20 which rests upon the inwardly extending flange 2| provided at the upper end of side plates 4 and 5 Bolts 22 extending through flanges 20 and 2| rigidly secure the tuyere supports l8 and I9 to sideplates 4 and 5, respectively. The upper end of each tuyre chamber IT has extending longitudinally thereof a pair of fluid conducting tubes 23. These tubes havesecured thereto a series of bars 24 which in turn rest upon tuyere supports I8 and I9, aswill appear more fully hereinafter.

The tubes 23, as shown in Fig. 1, extend downwardly and rearwardly to the end of the stoker, and then are bent downwardly and forwardly as shown at 25, and terminate at the lower ends thereof in a header 26 disposed near the bottom of the ash pocket 2'1. The upper ends of tubes 23 are bent vertically, as shown at 28, and extend upwardly along the inner surface of front wall II and terminate in a boiler (not shown) or, if preferred, in any suitable header which in turn is connected to the boiler.

The lower end of each retort 2 has provided therein a substantially horizontally extending dead plate 29. Mounted in cooling relation with each dead plate 29 are one or more fluid conduct ing tubes 39. These tubes extend rearwardly from a header 3| mounted in any suitable manner beneath the stoker, and are bent downwardly in substantially parallel relation with the tubes 23, and terminate at their lower ends in header 26. Headers 26 and 3| may be connected to the boiler by any suitable downtake and uptake con; nections 32 and 33 respectively.

Referring more particularly to Fig. 2, it will be noted that the tubes 23 have extending inwardly thereof fins 34 and 35. These fins are disposed in overlapping relation, thereby forming an air passage 35 therebetween through which draft air may enter the fuel bed. By arranging the fins in overlapping relation the passage of fuel siftings between the tubes is reduced to a minimum. Fins 34 and 35 are of sectional construction, as shown in Figs. 1 and 3, and therefore are not materially affected by expansion and contraction due to the variable temperature conditions of the furnace. Tubes 23 have also extending outwardly therefrom fins 31 and 33. These fins extend horizontally, and are then bent downwardly, as shown at 39 and 44,

and overlap the vertically extending projections 4| and 42 respectively of tuyere supports I3 and IS. The vertical portions 4| and 42 have provided at the outer sides thereof teeth or projections 43 and 44, which abut the inner sides of the portions 39 and 45 respectively, of fins 31 and 38, thereby forming a series of passages therebetween for draft air. The teeth or projections 43 and 44 also act as cooling vanes for the tuyere supporting members It and I9. Tubes 23 have alsoprovided thereon at spaced points along the length thereof downwardly extending bolts 45 and45, to which the supporting bars 24 are secured. These bolts are shouldered as shown at 41 and 48, to limit the downward movement of tubes 23. The reduced ends of bolts 45 and 48 extend through apertures provided in the bars 24, and lock nuts 49 provided at the lower ends thereof secure the bars in spaced relation with the tubes. The outer ends of bars 24 extend into open recesses 55 and 5|. provided at the inner sides of the supporting members I8 and I9 respectively. By this construction it is seen that the tubes 23 are effectively supported in position, and yet are free to expand and contract by virtue of the sliding supports provided by bars 24. Bars 24 also act as tie members to prevent lateral displacement of the tubes 23 under load. Draft air is supplied to the stoker by means of a plenum chamber 52, which in turn receives air under pressure from any suitable fan or blower mechanism (not shown) through a communicating passage 53.

' Fig. 4 discloses a somewhat modified constructionwherein two longitudinally extending fins 54 and 55 are provided on the inner side of tube 58. Fins 54 and 55 are disposed in spaced relationforming a longitudinally extending recess therebetween. Tube 51 has also provided at the inner side thereof a longitudinally extending fin 58 which enters the recess formed by fins 54 and 55. By this arrangement of tubes and fins passages of tortuous form are provided for draft air. The passage of fuel siftings between the tubes is also efiectively prevented. The tubes 55 and 5'! have also provided at the outer sides thereof longitudinally extending fins 59 and 6!! respectively. Fins 59 and 55 are similar in construction to the fins 38 and 31 respectively, provided on tubes 23, as shown in Figs. 1 and 2, and accordingly a detailed description thereof is unnecessary.

Fig. 5 discloses a further modification of the present invention, wherein the tubes 6| and 62 thereof have longitudinally extending fins 63 and 64 provided at the inner sides thereof. Fins 53 and 64 as shown, are disposed in spaced, overlapping relation. Also provided on fin 63 is a vertical extension 55 which is disposed in spaced relation with the inner end of fin 54. By this construction draft air is directed vertically into the fuel bed. Owing to the overlapping relation of fins 63 and 54 the passageof siftings between the tubes is reduced to a minimum. The outer sides of tubes 5| and 62 have also provided thereon longitudinally extending fins 66 and 61. The outer ends of fins 66 and 67 are spaced slightly from the inner ends of arcuate extensions 63 and 69 respectively, provided on tuyre supports 14 and ll, thereby providing additional openings through which draft air may enter the fuel bed.

Figs. 6 and 8 inclusive disclose a further modification of the present invention. In this construction the tubes 12 and '13 also have provided at the outer sides thereof fins l4 and 15 respectively, similar in construction to the fins 31 and 38 shown in Figs. 1 and 2. Tubes 12 and 13 have also provided thereon series of substantially horizontally disposed fins 16 and Ti respectively. The fins l5 and T! of each of said series are disposed in spaced relation along the tubes 72 and 13. The fins of each series extend into the spaces between the fins of the other series thereby forminga series of substantially horizontal passages for draft air. It will also be observed upon reference to Figs. 7 and 8 that fins l6 overlap longitudinally. The same is true of fins 11. Thus by this lateral, as well as longitudinally overlapping arrangement of the fins the passage of siftings between the tubes is reduced to a minimum.

Fig. 9 discloses a still further modification of the present invention wherein each tuyere chamber has provided at the upper end thereof three spaced tubes 8|, 82 and 83. Tube 8| has provided at the oppositesides thereof longitudinally extending fins 84 and 85. Tubes 82 and 83 have extending laterally from the inner sides thereof fins 86 and 81 disposed beneath and in overlapping relation with fins 84 and 85 respectively, and forming therewith passages for draft air. Tubes 82 and 83 have also extending laterally from the outer sides thereof fins 88 and 89, which, like fins 31 and 38, shown in Fig. 2, overlap the upper ends of the tuyresupports 90 and 9| respectively. Fins 88 and 89 are similar in construction and arrangement to the fins 31 and 38, and accordingly a detailed description thereof is unnecessary.

Tubes 8|, 82 and 83 have depending therefrom at spaced intervals bolts 92, 93 and 54,? to which are secured a supporting bar 95. Supporting bars 95 are mounted in the longitudinally extending recesses provided in tuyre supports 90 and 9|, and accordingly effectively support the tuyre section, and at the same time permit longitudinal expansion and contraction of the tubes.

The tuyre arrangement associated with tubes 8|, 82 and 83 are provided for the purpose of illustration to show that applicants invention is applicable to arrangements comprising more than two fluid conducting tubes. It is-obvious that other forms of fins, such as those shown in Figs. 4 and 5 and 6 to 8 may also be provided on arrangementsof this character without departing from the present invention.-

In all of the constructions hereinbefore described, the fins are welded to the tubes, thereby providing an intimate thermal contact between the fins and tubes. The fins are thus maintained relatively cool during operation of the furnace, and consequently burnouts are reduced to a minimum. The various constructions .hereinbefore. described also are of a simplified nature, and

therefore may be manufactured at a relatively low cost.

While the embodiments herein shown and described are admirably adapted to fulfill the objects primarily stated, it is to be understood that it is not intended to limit the invention thereto, since it may be embodied in other forms, all coming within the scope of the claims which follow.

What is claimed is:

1. A stoker grate, comprising a series of spaced, longitudinally extending tuyere sections, each of said tuyere sections consisting of a pair of longitudinally extending tubes, supporting means for said tubes comprising a pair of spaced side walls having longitudinally extending recesses at the inner sides thereof, supporting bars extending into said recesses and adapted for longitudinal movement therealong, and means integral with said tubes for securing said bars in spaced relation with said tubes, and fins extending inwardly from each of said tubes and forming therewith passages for draft air.

2. A stoker grate, comprising a series of spaced, longitudinally extending tuyre sections, each of said tuyre sections consisting of a pair of longitudinally extending tubes, supporting means for said tubes comprising a pair of spaced side Walls having longitudinally extending recesses at the inner sides thereof, supporting bars extending into said recesses and adapted for longitudinal movement therealong, means integral with said tubes for securing said bars in spaced relation with said tubes, and fins extending inwardly from each of said tubes and forming therewith passages for draft air, and additional fins extending outwardly from each of said tubes and forming with said side walls additional passages for draft air.

3. A tuyere construction for stoker furnaces comprising, a pair of longitudinally extending tubes arranged in spaced, substantially parallel relation, a pair of substantially longitudinally extending fins provided at the inner side of one of said tubes and parallel thereto, said fins being arranged in spaced relation, a substantially longitudinally extending fin, extending inwardly from the other of said tubes, said last mentioned fin extending into the space between said first mentioned fins and forming therewith and with said tubes a passage for draft air of substantially tortuous form.

4. A tuyre construction for stoker furnaces comprising, a pair of longitudinally extending tubes arranged in spaced, substantially parallel relation, fins extending inwardly from each of said tubes and parallel thereto and disposed in overlapping relation, a vertical projection extending upwardly from the lower of said fins and lying in spaced relation with the end of the fin on the adjacent tube, thereby forming therewith a restricted passage for draft air.

5. A tuyre construction for stoker furnaces, comprising a plurality of longitudinally extending fiuid conducting tubes arranged in substantially parallel relation, supporting means for said tubes, comprising a pair of spaced side walls, and means secured to said tubes and supported by said side Walls permitting longitudinal expansion and contraction of said tubes, and fins extending laterally from said tubes, said fins being integral with said tubes and being disposed in overlapping relation, thereby forming with said tubes passages for draft air, and said fins being so disposed as to permit independent expansion and contraction of each of said tubes.

6. A tuyere construction for stoker furnaces comprising a pair of longitudinally extending fluid conducting tubes arranged in substantially parallel relation, supporting means for said tubes comprising a pair of spaced side walls, longitudinally extending fins projecting inwardly from said tubes, said fins being disposed in overlapping relation thereby forming with said tubes passages for draft air, and additional longitudinally extending fins projecting laterally from the outer sides of said tubes, said last mentioned fins forming with the upper edges of said side Walls additional passages for draft air, and all of said fins being so disposed as to permit independent extension and contraction of said tubes.

7. A tuyre construction for stoker furnaces comprising a pair of longitudinally extending tubes arranged in substantially parallel relation, supporting means for said tubes comprising a pair of spaced side walls, fins secured to and extending inwardly from one of said tubes, fins secured to and extending inwardly from the other of said tubes and disposed in overlapping relation with said first mentioned fins and formin therewith passages for draft air, and fins extending outwardly from each of said tubes and forming with said side walls additional passages for draft air.

8. In a device of the class described, the combination of an inclined grate stoker comprising alternately disposed retorts and tuyere rows, each of said tuyre rows consisting of a pair of longitudinally extending tubes disposed in substantially parallel relation, a pair of spaced side walls for each of said tuyere rows for supporting said tubes, fins secured to and extending inwardly from one of said tubes of each of said tuyere rows. and fins secured to and extending inwardly from the other of the tubes of each of said tuyere rows and disposed in overlapping relation with said first mentioned fins and forming therewith and with said tubes passages for draft air.

9. A stoker grate, comprising a series of spaced, longitudinally extending tuyre sections, each of said tuyere sections consisting of a pair of longitudinally extending tubes, supporting means for said tubes comprising a pair of spaced side walls having longitudinally extending recesses at the inner sides thereof, supporting bars extending into said recesses and adapted for longitudinal movement therealong, and means for securing said bars to said tubes, and fins extending inwardly from each of said tubes and forming therewith passages for draft air.

10. A stoker grate, comprising a series of spaced, longitudinally extending tuyere sections, each of said tuyere sections consisting of a pair of longitudinally extending tubes, supporting means for said tubes comprising a pair of spaced side walls having longitudinally extending recesses at the inner sides thereof, supporting bars extending into said recesses and adapted for longitudinal movement therealong, means for securing said bars to said tubes and fins extending inwardly from each of said tubes and forming therewith passages for draft air, and additional fins extending outwardly from each of said tubes and forming with said side walls additional passages for draft air,

11. A tuyere construction for stoker furnaces comprising a plurality of longitudinally extending tubes arranged in substantially parallel relation, supporting means for said tubes comprising a pair of spaced walls, fins secured to and extending laterally from one of said tubes, fins secured to and extending laterally from another of said tubes and disposed in overlapping relation with said first mentioned fins and forming therewith passages for draft air, and fins extending outwardly from said tubes and forming with said sidewalls additional passages for draft air.

12. A tuyere construction for stoker furnaces comprising a plurality of longitudinally extending tubes arranged in spaced, substantially parallel relation, supporting means for said tubes comprising a pair of spaced side walls, spaced fins extending laterally from one of said tubes, fins provided on another of said tubes, said last mentioned fins extending into the spaces between said first mentioned fins and forming therewith and with said tubes passages for draft air of substantially tortuous form, and fins extending outwardly from said tubes and forming with said side Walls additional passages for draft air.

13. A tuyere construction for stoker furnaces comprising a plurality of longitudinally extending tubes arranged in spaced, substantially parallel relation, supporting means for said tubes comprising a pair of spaced, side walls, a fin extending laterally from one of said tubes, a fin extending laterally from an adjacent tube and disposed in overlapping relation with said first mentioned fin, a projection extending vertically from the lower of said fins and lying in spaced relation with the end of the fin on the adjacent tube thereby forming therewith a'restricted passage for draft air, and fins extending outwardly from said tubes and forming with said side walls additional passages for draft air.

JOSEPH S. BENNETT. 

